The proposed research will involve the synthesis of new, potentially nonaddicting analgesic agents. Structural areas will include the morphinoid, benzomorphan, oripavine, phenyl morphan, and phenyl benzomorphan series. Conformational analysis studies with computerized assistance will be employed as a primary guide for structure-activity correlations. Analgesic activity will be evaluated by hot-plate and jump-flinch methods. Addiction liability will be evaluated for active compounds by abrupt withdrawal and rat self-administration tests. Affinities for the isolated opiate receptor will be determined and also used as a basis for correlation of structure-conformation and biological activities.